Process q- molding lenses



E. D. THLYER AM] H. H4 STYLL.

PRDfiFSS 9F MOLDING LENSES APPLICATHUN FILED SEPT 6.19%.

1,308,820. Patented July 8, 1919.

1 E I f fwlmsssaszi yaw fHgfarD. Yiz'liyer and g Harry H. 5151! f f mdnm ma am Weir UNITED STATES PATENT OFFICE.

EDGAR D. TILLYER AND HARRY H. STYLL, OF SOUTI-IBRIDGE, MASSACHUSETTS,

ABSIGNOBS TO .QMERICAN OPTICAL COMPANY, OF SOUTHBRIDGE, MASSA- CHUSETTB,A. VOLUNTARY ASSOCIATION MASSACHUSETTS.

PROCESS O? MOLDING LENSES.

Specification of Letters Patent.

Patcutci'l July 8. 19.1.9.

Application filed September 8, 1916. Serial No. 118,773.

To all whom it may concern:

Be it known that we, EDGAR D. TILLYEXP and llnnnrH. STYLL, citizens ofthe United States, residing at Southbriclgc, in the county of lVorccsterand Eitate of Massachusetts, have invented certain new and usefulImprovements in Processes of Molding Lenses, of which the following is aspecification.

This invention relates to improvements in method of ma'mifacturingophthalmic lenses, and has for its leading object the provision of animproved sim )lified method of so molding or shaping op ithalmic lensesthat at least one oi the molded surfaces shall pos sess a suilicicntpolish to be commercially usable as a lens without subsequent grindingor other operations thereon.

Av further object of the invention the provision of an im roved methodby which a single complete y formed lens may be manufactured entirely bymolding if desired, or by which a plurality of lenses may beruzu'uifaetured in semi-finished form if preferred.

A. :t'urtlzer object of the invention is the provision of improvedmechanism for carryin r out our novel method of. constructing oihthalmic lenses.

Other objects and advantages of our im proved method of and apparatusfor constructing ophthalmic lenses should he rcadily aimarcnt byreference to the following speci ication taken in connection with theaccompanying drawings,and it will be understood that we may make anyvariations in the several steps of the process or in the machinery forcarrying out the process, within the scope of the appended claimswithout in any Wise departing from or exceeding the spirit of ourinvention.

Figure I represents a fragmentary semidiagrammatic illustration of onestep in the manufacture of the lens.

Fig. II represents a view of the blank heating and transferring means.

Fig. III represents a vertical sectional view illustrating one form ofmachine, which may be mployed in the carrying out of our invention.

Fig. IV represents an enlarged detail viewv of the air controllingvalve.

Fig. V represents: a view of a spinning mold.

Referring especially to our novel process or method of formingophthulnuc lenses by molding: We are aware that prior to our inventionit has been customary to mold lumps or disks of glass into substantiallythe sha e of a finished lens, but hitherto these blah s have always hada rough, somcwluu pitted surface as brought from the mold, as a resultof their contact with the mold. and consequently have not been usahiewithout suhsequent grinding. lVe i'urhcr miderstand that prior to ourpresent invcnlion attmnpts hare heel: ma ls to polish. lenses and t enbend the same under influence of heat to vary the curve:- or shape ofthe lens Olin-h, This likewise has been. attended with considerabledisadvantages. since the lenses so produced while in some inst noes dueto the" use of exceptional care in their construction may have provedusable, have almost uni rcrsully been. rendered unfit for use a firstclass satisfacti'ary due to the factthat contact with the mold always toa greater or less degree injured the polished surface so that thesurface was no longer a true lens surface, but was substantiallyimpaired to render its use before the eye an unsatisfactory if notdangerous priiicedure, while on account of the difliculties attendantupon its even semi-sl'lccessiul operation, lenses could not hecommercially prmlucerl in accordance with this process.

By the use of our present process, however, and by the interposition ofa cushion or film of vapor between the face of the mold and the surfaceof the lens, the surface of the lens is in nowise injured or distortedby contact with the mold, but a fire polished surface produced which isrfeetly satisfac tory for a surface of an ophthalmic lens, and in allessential respects equal to a specially ground and polished lenssurface.

In order that the carrying out of our proc ess may be better understoodwe have designed and herewith illustrated certain mechanism for thecarrying out of the process, it being understood, however that theprocess is entirely independent of the particular machinery hereillustrated, since we realize that other machinery or apparatus could beemployed with equally satisfactory results, and the essential inventionresiding n the up )rcciatiou of the fact the a satisfactory sur acecould be produced on an ophthalmio lens by molding and in the process ofproduction of this surface.

Referring to the apparatus for carrying out our JIOCGSS, as illustratedin the drawings, an in which similar characters of reference areemployed to denote corresponding parts throughout the views, the numeral1 designates a base mold section which has an upper surface 2 of thedesired curve to be produced on the lens, said surface 2 being suitablycoated with a thin layer of asbestos or other suitable absorbentmaterial 3 having its inner face shaped to the exact curve to beproduced on the lens. Disposed above the mold section 1 We have shownthe plunger 4, which if desired may have the second curved surface 5with the coating 6 to engage and shape the upper face of the lens.

It will be understood, however, that if desired we may employ merely thelower mold l uithout the plunger 4-, allowing the lens to set down ontothe mold by its own weight in place of being pressed there aflainsl. Ineither event we have shown as disposed at the side of the mold andplunger tln liquid supply pipe 7 having the spray nozzles 8 and 9directed respectively toward the absorbent coatings 3 and 6 of the moldl and plunger 4, whereby these coatings may be readily sprayed tosaturate the same with suitable moisture of Water, oil or the like, asmay be preferred. It will he understood, however, that in the carryingout of our process it is not necessary to employ the spray nozzles,since the absorbent coatings may be moistened by the use of a. sponge,brush or in any other suitable manner.

In the further carrying out of our process the lens is suitably heated,as by being )lacod within the furnace or heater 10. n the event that itdesired to change the shape of a lens already ground and olished, as thelens blank 11 shown in Fig. I for example, the blanl: in place of beingrested in the oven or heater with its polished surface in contact withthe floor or grating of the oven, may be suspended as by the tongs 12engaging the edges of the lenses and held on a. suitable rest 13, aspring 14 holding the jaws of the ton in clamping engagement with theedges of the lens. In this manner the lens is heated and after beinheated is moved by the tongs and place upon the mold 1, being then ifdesired engaged by the plunger 4 to firmly press the lens down againstthe mold and shape the upper surfaceof the lens, as should e bestunderstood by reference to Fig. III.

Attention is here invited to the fact that in Fig. III the mold l isshown as having the depending stem 15 surrounded by the spring 16,allowing the mold to yield downward within the tubular casing or shell17 which serves to engage the edges of the lens blank 11 to preventspreading thereof under the pressure of the plunger 4 so that the upperand lower surfaces of the lens will both have the desired curve, whileupon raising of the plunger 4 the spring 16 will shift the mold upwardto bring the lens above the shell 17.

It is to be understood that in the carrying out of our process, theabsorbent coating of the mold that both mold and plunger are employed,are suitably saturated. When the spray nozzles are employed for thispurpose the coatings may if desired be saturated with steam, thusraising the temperature of the mold nearer that of the glass so therewill be less liability of cracking or strain on the blank on account ofthe heated plastic blank being suddenly brought into contact with thecold mold or a hen ed oil may he used for the saturation. In any event,the absorbent surfaces having been saturated the blank is placed inposition and if a plunger is uscd theplunger 4 is brought down, asillustrated in Fig. III, in which the mold has been pushed downward bythe blank and plunger within the shell 17 which engages the side wallsof the blank to limit its spreading movement and insure the properthickness and upper and lower curves of the blank. In Fig. III theaction of our improved process has been exaggerated for purposesofillustration. By reference to this figure it will be noted thatbetween the surface 3 and the lens blank 11 and between the surface 6and the lens blank 11 is a cushion of vapor 18, which it is true inactual practice will be so thin as to be in'ipcroeptiblc, but which atthe same time will place a thin film or covering between the surfaces 3and (i and the fa es of the lens, this vapor being gone eratcd by theapproach of the hot blank 1.1 to the surfaces, and continuing to begenerated until the surfaces have been so cooled that they will nolonger be in any Wise injured by contact with the absorbent coatings 3and 6.

It will be appreciated, however, that inasmuch as the vapor filmsconform exactly to the curve or shape of the absorbent surfaces fromwhich they rise, that the lens blank will be properly molded to theexact desired curve and at the same time will ac quire what may betermed a fire polish, or in other words, a high glazed polish suitablefor optical purposes.

It will be noted in connection WithFig. III that we have shown a treadleor the like coupled to actuate the plunger 4 while there is an operatingarm 19 associated with the main treaxlle 20 in such manner that presandof the plunger, in the event sure of the foot on the treadle to depressthe plunger will serve to temporarily open the controlling valve 21 forthe spray supply lines and temporarily sp ay the sur aces 3 and 6.

Likewise, as the plunger is raised, and in order to insure substantiallyuniform cooling of the lens blank as it is raised upward by the actionof the 'sprin 16 on the mold 1, we have placed on the s iell 17 theblower nozzle or nozzles 22 controlled by the valve 23 and adapted toproject a current or blast of air across the lens to suitably cool same.This blast is controlledby the valve handle 24 havin pivoted thereto thelatch end 25 engaged y the pin 26 on the plunger as the plun er rises totemporarily open the valve and low it to slip off the pin 26 and closebefore the plunger reaches its upper limit of movement, the pivotalconnection between the valve handle 24: and member 25 being such thatthe plunger will swing the member downward on its pivot 11 on depressionof the plunger without actua ing the air spray, a spring 27 returning itto raised posltion where it will been aged by the pin on the plunger onupward movement of the plung In Fig. V we have illustrated onemodification of our process, in which the plunger member 4: is suitablyrotatably mounted and driven with a spinning movement so that the lensis placed on the mold or support 1 and the spinning lunger withsaturated absorbent surface 6 rought down onto the lens s inning aroundover it to insure correct 5 aping of its upper exposed surface.

From the foregoing description taken in connection with the accom anyingdrawings, the generic features 0 our improved process should be readilyap arent, and it will be seen that broadl spea ing the process consistsin the suitable preparation of a mold having an absorbent surface orsurfaces which may be adapted to give off a steam or like protectingvaiplgr to form a film protecting the surface In contact on bringin of aheated lens blank into proximity t ereto, in suitably heating the lens 7blank and placing the blank above the mold and in causing the blank toconform to the shape of the mold, either by its own weight as it isplaced thereon in heated plastic con-- dition, or by the application ofpressure thereto, or, if preferred, by making the mold in such shapethat the lens may be blown from molten glass directly against the moldsurface, the essential features in an event hein the heating or bringingof t e lens blan to a plastic condition and the placing of the plasticglass in such relation to a vapor protected mold. that the glass willreceive the sh" e of the mold and at the same time have a l i 'repolished surface or its own polished surface preserved on account of theprotecting vapor, preventing actual contact between the surface of thelens and the surface of the mold, while the lens surface is in lastic orimpression receiving condition.

e claim:

1. The process of forming an ophthalmic lens, conslsting in heating theglass stock, preparing molding surfaces therefor by moistening thesurfaces, placing the glass stock between the surfaces while in heatedcondition, bringin the moistened surfaces toward the glass w iereby acushioning film is provided preservin the fire polish of the glass whileshaping tile stock to correspond with the shape of the mold, withdrawingthe shaping pressure and projecting an air blast on the molded lens.

2. The process of forming an ophthalmic lens, consisting in heating theglass stock, bringing the glass stock and a mold into close proximit onewith the other, producing a vapor film between the adjacent surfaces ofthe mold and glass stock, withdrawing the shaping pressure andprojecting an air blast on the molded lens.

In testimony whereof we affix our signatures in the presence of twowitnesses.

EDGAR D. TILLYER. HARRY H. STYLL.

